A spokesman from SECAmb said the man, thought to be around 60-years-old, had suffered an arm and leg injury and was airlifted to St George's Hospital in Tooting after being treated at the scene.

More than 20 emergency service personnel worked for two hours to rescue the worker, who was understood to have been involved in routine rail maintenance.

A police helicopter had to land on the railway line in order to get emergency crews to the scene.

The rescue teams worked in difficult conditions on top of a steep railway embankment, and they eventually had to stretcher the injured man underneath the train to get him to safety via a nearby rail bridge.

According to the National Rail Twitter account, lines were blocked at Redhill and delays were reported across a number of services until the afternoon.